I've used sites that are trying something similar to find bands in the past. So I think I'm pretty close to the target market (or have been in my past). I don't want to post bass-player-looking-for-band on Craigslist or such -- did it once, and you get swamped by shitty bands who mostly still don't send any audio.
As a bass player, I want to hear if the singer can sing, and if the sketches of songs are good.
I can also play all of the standard band instruments at varying levels of competence, but I'm not much of a songwriter. What people expect from bass players and drummers is that they are good at catching things quickly and writing interesting parts.